This publication presents and discusses some of the key information available in the newly created Database on Immigrants in OECD Countries (DIOC). The many graphs and tables include data on: immigrants’ demography including age, gender and duration of stay; and their labour market outcomes including labour market status, occupation and sector of activity.

The book consists of nine thematic chapters, each including a brief description of sources, and a discussion of cross-country differences. The chapters also include a short analysis of specific issues relevant to the data, such as the gender dimension of "brain drain", the international migration of health professionals, and the role of low-skilled foreign-born workers in domestic services.

An introductory chapter provides an overview of the data to present a picture of international migration to the OECD from four regions: Africa, Asia, and Latin America and from within the OECD area. A methodogical note completes the report by summarizing the different sources and methods applied and explaining the structure of the new DIOC.

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The database provides figures on the total population by country of birth and citizenship (foreigners and nationals). Data are presented for all OECD countries (except Iceland and Korea) around the year 2000. The breakdown according to nationality and country of birth is incomplete in the case of Germany, Japan, Mexico and the United Kingdom (see Annex A for further information).

The database provides the age structure of the population aged 15 and over, by country of birth, gender and educational level. Age is given by five-year age groups up to 70 and an additional group records people over 70. This detailed information is available for 26 countries, while data on three broad age groups (15-24, 25-64 and 65+) are available for two additional countries (see Annex A for details).

The database provides the educational level of the population aged 15 and over, by country of birth and gender. For 27 countries, there are three categories of educational attainment: primary or lower (ISCED 0/1/2), secondary (ISECD 3/4) and tertiary (ISCED 5/6). Moreover, there is additional information for 20 of these countries that allows differentiating doctorate holders from other persons with tertiary education (see Annex A for methodological details).

The database contains information on the duration of stay of the population aged 15 and over, by detailed country of birth and gender. This information is available through census data for 14 countries and through labour force surveys for nine countries. In order to harmonise these two types of sources, a three-category classification has been defined: less than five years, five to ten years and more than ten years. For the countries with census data, more detailed information, with a six-category classification, is available. It is important to note that, for a couple of countries, the data on duration of stay are missing for a significant share of the foreign-born population. This is particularly the case in Italy, Greece, Ireland and France.

For all persons aged 15 and older, labour market status was recorded in the data collection by country of birth, gender and education level. The data distinguish persons employed, unemployed and inactive in all countries. For 21 of the 28 OECD countries covered in this publication, there is additional information on the main reason for inactivity (study, retirement, other). Employment rates, participation rates and unemployment rates are calculated for people aged 15 and older, according to the definition used in the relevant source (see annex for methodological details).

For all persons employed aged 15 and older, occupation was recorded by country of birth. Occupations are defined on the basis of the International Standard Classification of Occupations (ISCO) at the three-digit level. At the two-digit level, the data are crossclassified by education levels and gender. Data are available for the 28 countries covered by the publication, although they are only available the at the one-digit level for Italy. For Japan, Turkey and the United States, national classifications cannot be matched to ISCO even at aggregate level. For the purposes of this publication, the occupations have been regrouped into three categories corresponding to three different levels of qualification: professionals (ISCO major groups 1 and 2), technicians (ISCO major groups 3 and 4) and operators and labourers (all other groups).

Data on the sectors of activity of the employed population aged 15 and older are available for 26 of the 28 countries covered in this publication (Germany and Japan are missing). Sectors of activity are available according to the International Standard Industrial Classification (third revision) at the two-digit level, which lists a total of 60 sectors. Some countries have only been able to provide data at the one-digit level, thus for only 17 sectors. For the Czech Republic, France, Italy, New Zealand, Switzerland, Turkey and the United States, data on the sectors of activity were provided on the basis of national definitions and required some adaptation. For Belgium, Germany and the Netherlands, data are based on estimates from national labour force surveys, which do not allow all distinctions to be made: as a result, there is a significant number of unknown sectors of activity for these countries. Missing values account for over 10% of Switzerland’s data.

For the persons aged 15 and older with a tertiary education, the field of study was recorded by place of birth, gender and educational level. Fields of education have been aggregated in the following categories: i) education, health and welfare; ii) humanities, arts, social sciences, business and law; iii) science, engineering, manufacturing, construction and agriculture; and iv) general programmes and services. For 15 OECD countries, the distribution by field of study among tertiary-educated persons is presented by birth status or main countries of origin.

The data collected from population censuses and registers in participating OECD countries allow a count of migrants by country of birth (for more than 220 countries of origin) in the OECD area. Emigration rates by gender, age and educational level can then be computed based on complementary information on origin countries. In particular, they provide an estimate of the scope and characteristics of the "brain drain" to OECD countries (the share of people holding a tertiary degree who have emigrated to the OECD area) by country of birth.

All the thematic tables included in this publication were extracted from the Database on Immigrants in OECD Countries (DIOC). This database is made up of seven separate files (A to G), each covering a specific theme. As shown in Table A.1, each file includes a number of variables, which makes it possible to generate a great variety of cross-tabulations on the population characteristics within the OECD countries by country of birth. This publication presents a selection of these cross-tabulations.